typedef struct tagSPATIALFLT 
   L_UINT uStructSize;  /* size of this structure */ 
   L_INT fltDivisor; /* sum divisor */ 
   L_INT fltBias; /* sum bias */ 
   L_UINT fltDim; /* filter dimensions */ 
   L_INT fltMatrix[1]; /* array of filter coefficients */ 

The SPATIALFLT structure lets you design your own filter to use with the L_SpatialFilterBitmap function. Click here to view a diagram in a separate window that shows how the weights are applied in a typical Prewitt gradient directional edge enhancement operation.


pSPATIALFLT is a pointer to a SPATIALFLT structure. Where the function parameter type is pSPATIALFLT, you can declare a SPATIALFLT variable, update the structure's fields, and pass the variable's address in the parameter. Declaring a pSPATIALFLT variable is necessary only if your program requires a pointer.

It is beyond the scope of this documentation to explain how applying various weighting factors affects an image. If you specify your own filter, you should refer to a textbook on image processing. For example, Digital Image Processing: Principles and Applications, by Gregory A. Baxes.

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